Introduction:

Proteinuria is a kidney damage marker. KDIGO 2012 categorizes 24h proteinuria (PER), mg/ 24h, or proteinuria / creati-ninuria ratio in isolated sample (PCR), mg / g, in: A1, normal-slightly increased: <150; A2, moderately increased: 150-500; A3, severely increased:> 500. PER is the gold standard, PCR was incorporated to avoid 24h collection but the numerical equivalence between both is controversial. The maximum normal value, 150 mg / 24h, has diagnostic / prognostic relevance in Chronic Kidney Disease.

Objectives:

to determine in a sample of students: a) correlation of PCR in first morning urine with PER, b) cut-off value (VdC) of PCR predictor of PER = 150 mg / 24h, c) concordance between both methodologies for categorization A according to the PCR values of KDIGO 2012 and the VdC found.

Methodology:

Descriptive, analytical, cross-sectional study. Sample: 51 students. Determinations in 24h urine and first morning. Proteins: Red Pirogalol-Molybdate method; creatinine: Jaffé kinetic. Correlation: Spearman coefficient; Concordance: Bland-Altman and kappa. VdC: ROC analysis (receiver operating curve). Programs: Excel and Medcalc. 95% CI, p <0.05.

Results:

Proteinuria (median / interquartile range), PER (mg / 24h): 106.00 / 83.64-137.82; PCR (mg / g): 58.00 / 50.50-87.00; p = 0.025; Spearman coefficient: 0.5540; Bland-Altman mean of the differences (PER-PCR): 31.4. ABC = 0.883 (95% CI 0.762-0.956), VdC = 82 mg / g, S=90 %, E=82.9 %, RP + = 5.27, RP- = 0.12. Concordance in categorization A: kappa using PCR 150 mg / g: 0.106 (IC95% -0.134-0.347), poor-mild; kappa using VdeC found: 0.4568 (IC95% 0.2063-0.6505), mild-considerable.

Conclusions:

The concordance in categorization A improves using the VdC. It emphasizes the importance of not using as equivalent PCR = 150 mg / g and PER = 150 mg / 24h to differentiate normal from increased proteinuria but to establish in each laboratory the corresponding VdeC.

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